<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style>
        div{
            width: 200px;
            height: 200px;
            background: red;
            /*  */
            transition-property: height background;
            /* 动画时间 */
            transition-duration: 2s;
            /* 速度 */
            transition-timing-function: linear;
            /* 延时 */
            transition-delay: 2s
        }

        div:hover{
            height: 400px;
            background-color: yellow;
        }
    </style>
</head>
<body>
    
    <div>

    </div>
</body>
</html>